+define arbitrary actions for commands like "update", "checkout", or "commit".
+
+B<mr> cds into and operates on all registered repsitories at or below your
+working directory. Or, if you are in a subdirectory of a repository that
+contains no other registered repositories, it will stay in that directory,
+and work on only that repository,
+
+The predefined commands should be fairly familiar to users of any revision
+control system:
+
+=over 4
+
+=item checkout (or co)
+
+Checks out any repositories that are not already checked out.
+
+=item update
+
+Updates each repository from its configured remote repository.
+
+If a repository isn't checked out yet, it will first check it out.
+
+=item status
+
+Displays a status report for each repository, showing what
+uncommitted changes are present in the repository.
+
+=item commit (or ci)
+
+Commits changes to each repository. (By default, changes are pushed to the
+remote repository too, when using distributed systems like git.)
+
+The optional -m parameter allows specifying a commit message.
+
+=item diff
+
+Show a diff of uncommitted changes.
+
+=item list
+
+List the repositories that mr will act on.
+
+=item help
+
+Displays this help.
+
+=back
+
+Actions can be abbreviated to any unambiguous subsctring, so
+"mr st" is equivilant to "mr status", and "mr up" is equivilant to "mr
+update"
+
+Additional parameters can be passed to other commands than "commit", they
+will be passed on unchanged to the underlying revision control system.
+This is mostly useful if the repositories mr will act on all use the same
+revision control system.